秦岭山地巴山冷杉林的更新特征及影响因子

摘要

【Objective】 This paper carried research on regeneration characteristics and regeneration impact factors of the Abies fargesii forests of Qinling mountain,to provide theoretical reference for judging the nature regeneration trend of the forests and near-nature restoring.【Method】 Through the investigations of the typical sample plots,taking the important value of tree species and woody plant regeneration layer,diameter structure of dominant tree species and regeneration characteristics of woody plant layer as the index,we analyzed regeneration characteristics of A.fargesii Franch.And we also analyzed the effects of different factors on the regeneration layer by the densities of the regeneration layer.【Result】 The results showed that the important value of A.fargesii Franch was 193.96%,which was the constructive species.Betula albo-sinensis var.septentrionalis was the dominant species.Both of the two tree populations were missing at of 0-≤5 cm in the diameter level structure.There were 7 tree species in regenerated layer,just occupying 17.9% of the total number of species.The important value of Fargesia spathacea was 90.78%.The main regeneration type in understory was shrub sprouting.When the altitude rose from 2 300 m to 2 726 m,the density of seedings gradually increased.While the density of seedings decreased with the altitude ascending,the density of saplings showed the decreasing trend with the altitude increasing.When the stand density went up to 880 stems/hm2 from 460 stems/hm2,the density of saplings was at the maximum value.After that,as the stand density increased,the density of saplings fell.However,the saplings density reached the peak at the minimal stand density,then dropped substantially.With the slope changing direction from the sunny slope to the semi-sunny slope and then the shady slope,the density of seedings was up to the highest point at the semi-sunny slope SE84°,then showing a decline trend.In contrast,the density of saplings decreased in the process.【Conclusion】 The regeneration of tree species of the Abies fargesii forests of Qinling mountain was poor,and the forests were in the degenerate stage.The over growth of F.spathacea in the understory affected seriously the development of tree species.Altitude,stand density,slope direction were the main influencing factors on regeneration.%【目的】研究秦岭山地巴山冷杉林的更新特征及其更新影响因子,为巴山冷杉林的天然更新趋向判定及近自然化恢复提供理论依据。【方法】通过典型样地调查,以乔木层与灌木层重要值及乔木径级结构、林下木本植物更新特征为指标,分析巴山冷杉林的更新特征,并通过林下木本植物更新层的密度分析不同因子对其的影响。【结果】乔木层中巴山冷杉（Abies fargesii）重要值为193.96%,为建群种,亚优势种为牛皮桦（Betula albo-sinensisvar.septentrionalis）,二者的径级结构中0～≤5cm个体缺乏。林下更新层中乔木树种有7种,仅占总种数的17.9%,箭竹（Fargesia spathacea）的重要值最高,达到90.78%;林下的更新方式以灌木萌生为主,该森林群落乔木更新较差,处于衰退阶段。当海拔从2 300m上升到2 726m时,林下幼苗密度逐渐增加,随着海拔继续升高,幼苗密度却呈逐渐下降趋势;而幼树密度随着海拔的上升一直呈下降趋势。当林分密度从460增加到880株/hm2时,林下自然更新的幼苗密度达到57 000株/hm2,其后随林分密度的增加逐渐减少;而幼树密度在林分密度最小（460株/hm2）时达到36 500株/hm2,随后随林分密度的增加而急剧下降。当坡向从阳坡SE15°转至半阳坡SE84°时,林下幼苗密度呈现增加趋势,继续转向阴坡NE32°的过程中,则呈现递减趋势;林下幼树密度在由阳坡转向阴坡的过程中逐渐减少。【结论】秦岭山地巴山冷杉林乔木更新较差,处于衰退阶段;林下箭竹的过度生长对乔木树种的拓殖有严重抑制作用;海拔、林分密度、坡向等是该林分天然更新的主要影响因子。